This invention relates to intranasal therapy using synthetically produced short peptide sequences which inhibit HTLV-III/LAV (hereinafter referred to as HIV) binding to human cells by blocking receptor sites on the cell surface, and thus preventing viral infectivity of human lymphocytes and other cells. The peptides, while preventing infectivity, also induce antibody production against the envelope protein of the HIV virus when appropriately coupled with carriers. Hence, these peptides also have use as vaccines to prevent development of Acquired Immune Deficiency Syndrome (AIDS). Monoclonal antibodies to the peptides could also be used as diagnostic agents to identify the HIV virus. Hence, peptides and antibodies to the peptides would have use in preparing test kits for identification of HIV carriers or persons suffering from AIDS.
The complete nucleotide sequence of the AIDS (HIV) virus has been reported by several investigators. (See Lee Ratner et al., Nature 313 p. 277, January 1985; Muesing et al., Nature 313 p. 450, February 1985; and Wain-Habson et al., Cell 40 pp. 9-17, January 1985) The envelope gene has been associated particularly with antigenicity and infectivity. However, the envelope portion is also known to have regions which are highly divergent. The HIV virus envelope glycoprotein has been shown to affix non-covalently to the brain membranes of humans, rats, and monkeys and to cells of the immune system.
The realization that viruses may exert cell and tissue tropism by attachment at highly specific sites on cell membrane receptors has encouraged investigators to seek agents which would bind at the viral receptor sites of cell membranes and thus prevent binding of a specific virus to these cells. A demonstration of specific receptor-mediated vaccinia virus infectivity being blocked by synthetic peptides has been previously demonstrated (Epstein et al., Nature 318: 663-667).
The HIV virus has been shown to bind to a surface molecule known as the CD4 or T4 region, which is present on various cells susceptible to HIV infection, including T lymphocytes and macrophages. (See Shaw et al., Science 226, pp. 1165-1171 for discussion of tropism of HTLV-III.)
In addition to symptoms arising from immunodeficiency, patients with AIDS show neuropsychological defects. The central nervous and immune systems share a large number of specific cell-surface recognition molecules, serving as receptors for neuropeptide-mediated intercellular communication. The neuropeptides and their receptors show profound evolutionary stability, being highly conserved in largely unaltered form in unicellular organisms as well as higher animals. Furthermore, the central nervous and immune systems show common, CD4 (T4) cell-surface recognition molecules which serve as receptors for the binding of HIV envelope glycoprotein (gp 120). Since the same highly conserved neuropeptide informational substances integrate immune and brain function through receptors remarkably similar to those of HIV, we postulated that a very similar amino acid sequence between the HIV glycoprotein gp 120 and a short peptide previously identified in another context from the envelope region of the Epstein Barr-Virus might indicate the core peptide essential for viral receptor binding. It was postulated that such a peptide would be useful in preventing infection of cells with the HIV by binding with receptor cells and blocking the binding of HIV gp 120, that such peptides binding to the receptor sites would give rise to production of antibodies directed to the peptide sequence, and that those peptides might be used to provide immunological basis for prevention of AIDS.
Recent basic research has demonstrated that common receptor and transmitter mechanisms may be found in the central nervous and cellular immune systems. Certain viruses may be able to utilize these common pathways to enter the cells in the brain as well as circulating leukocytes. Peptide T is a modified octapeptide homologous to a subunit sequence of Vasoactive Intestinal Peptide (VIP) described by Pert, et al (PNAS, Vol. 83, pages 9254-9258 (1986)) that was found to exist in homologous form in the 120 Kilodalton envelope glycoprotein (gp 120) of all HIV isolates thus far sequenced. Autoradiographic mapping with labeled gp 120 has shown greater binding in VIP receptor rich areas. In vitro studies have demonstrated that VIP and Peptide T inhibit both the binding of gp 120 to brain tissue and HIV replication in cell culture. Peptide T in picomolar concentrations has been shown to block the neurotoxic effects of gp 120 in cell culture and animals. Intravenous Peptide T in doses up to 224 mg/day has shown no toxicity and has resulted in improved neurocognitive functioning in the HIV-infected patients participating in a recent study. Rosen, M I, et al Addiction (Inpress)--Brenneman, D. et al (Nature 335 page 639-642, 1788; Bridge, T P et al, Lancet II page 226-227 (1989)--Hill, J. M. et al (abstract) Sixth Intl. conf. on AIDS vol. 1, page 330.
The clinical relevance of this observation has been recently underscored by the finding that HIV-1-induced neurotoxicity appears to be associated with gp 120-CD4 binding resulting in increasing intracellular free calcium. Calcium channel blockers such as nimodipine have been shown to antagonize this effect.
The present invention relates to the use of Peptide T in treating HIV-infected patients. These initial intravenous studies involved 20 AIDS and ARC patients who received the drug for one to three months without consistent changes in p24 antigen or immunologic measures but who manifested improvements in neurocognitive function and diminution of constitutional symptomatology.
The present invention further describes intranasal therapy using Peptide T (for example, at dosage levels of about 1.2, 6, and 30 mg./day) in symptomatic HIV-infected humans over a six month period.
Furthermore, the invention relates to intranasal use of Peptide T to prevent, halt, and/or to reverse the immunological, virological and/or clinical manifestations of HIV infections as determined by monitoring clinical symptoms, frequency or severity of infections, disease progression, neurocognitive improvement, or serial T helper lymphocyte counts.
Additionally, the present invention relates to the treatment of Tropical Spastic Paresis (TSP) with Peptide T. Treatment of TSP is also accomplished by intranasal therapy using Peptide T. The treatment of TSP with Peptide T has resulted in substantial reversal of the symptoms associated with the disease e.g., paralysis of feet and legs. Improvements in bladder and sexual function were also observed as well as a decreased deterioration in memory and attention deficits.